INFLIGHT OXYGEN-SATURATION DECREMENTS IN AEROMEDICAL EVACUATION PATIENTS

Past studies have shown that patients with severe chronic obstructive pulmonary disease (COPD) may experience oxygen desaturation at the cab in altitudes of pressurized aircraft. Because COPD can be associated i n varying degrees with ischemic heart disease (IHD), and because the c onsequences of hypoxia in such patients can be significant, the ground and altitude pulse oximeter readings of 24 ambulatory aeromedical eva cuation patients with known or suspected IHD were recorded. Written, i nformed consent, as well as smoking history and respiratory spirometry were obtained preflight. Results showed a mean saturation decrease of 5.5 percentage points (95% CI: 4.5-6.4). The mean cabin altitude wets 6900 ft (range: 2500-8100). No patients experienced clinical symptoms . Of 24 patients, 3 were given supplemental oxygen when their Inflight oximetry readings consistently read below 90%. Saturation decrease di d not correlate specifically with age, smoking history, the FEV1/FVC r atio, or the inflight cabin altitude, We conclude that ambulatory aero medical evacuation patients with known or suspected IHD may demonstrat e mild decreases in oxygen saturation which are not readily predicted by age, smoking history, preflight spirometry, or inflight cabin altit ude. Pulse oximetry compatible with aircraft electrical systems may pr ovide useful inflight monitoring on such patients.